Using 9" retaining wall to build garden room
- Thread starter AFT4B
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.https://www.brick.org.uk/uploads/downloads/s-design-of-brickwork-retaining-walls.pdf
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No. The horizontal DPC bedded onto the wall will be a slip point and a no-no, regards retaining.
A little light reading , the examples around page 16 will give you a view on wall thicknesses although your proposals are slightly off the beaten track and foundation design are in a different league
Something like this would be more suitable, in principle, except add another block width to the bottom so the wall is stepped in width as you go down to your 1.5m depth.
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Building a garden room directly against a retaining wall is risky because of damp. Even with a DPC tray, water from the flower beds can soak through the brickwork over time. You need a tanking system or a waterproof membrane on the external side of the wall to keep the interior dry.
Further to the above if you are au fait with spreadsheets I have put one together based on the examples around page 16 to determine wall thicknesses required based on various parameters depending which ones are chosen. Unfortunately I can only put up a print of the spreadsheet so the sheet would have to created from scratch. The info in the black box area show the actual formulae used in the spreadsheet calcs.
I've read enough to decide against the idea of building off the top off the retaining wall. We have just enough room to extend the concrete pad and potentially leave some gap to build the garden room. Thank you all for your replies.
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